Hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing formation. Once a wellbore has been drilled, the well must be completed before hydrocarbons can be produced from the well. A completion involves the design, selection, and installation of equipment and materials in or around the wellbore for conveying, pumping, or controlling the production or injection of fluids. After the well has been completed, production of oil and gas can begin.
Sealing systems, such as packers or anchors, are commonly deployed in a well as completion equipment. Packers are often used to isolate portions of a wellbore from one another. For example, packers are used to seal the annulus between a tubing string and a wall or casing of the wellbore, isolating the portion of the wellbore above the packer from the portion of the wellbore below the packer. Packers are actuated by hydraulic pressure transmitted either through the tubing bore, annulus, or a control line. Other packers are actuated via an electric line deployed from the surface of the wellbore. Furthermore, packers have been used that employ elements that respond to the surrounding well fluids and swell to form a seal. Many different materials have been disclosed as capable of having this feature and some designs have gone further to prevent swelling until the packer is close to the position where it will be set. Often swelling packers have a limited ability to create contact pressure between the tubular and wall of the wellbore. When a wellbore has non-uniformity and eccentricity, as often encountered in openhole wellbores, the swelling packer's ability to form contact pressure between a tubular and the wall of the wellbore is further limited. The amount of contact pressure is a factor in the packer's ability to control the level of differential pressure between portions of the wellbore.
In addition, the sealing element of swellable packers often extrudes longitudinally as the swellable packer expands radially. The longitudinal extrusion of the sealing element within the swellable packers can reduce the packer's ability to handle differential pressures between portions of a wellbore.
A need exists, therefore, for a swellable packer that can be used in an openhole or cased wellbore and that prevents the sealing element from extruding longitudinally as the packer expands radially.